The present invention relates to a fluid spraying apparatus, and has particular reference to fluid spraying apparatus of the kind suitable for use in dislodging or resuspending sludge accumulated on the bottom of a crude oil storage tank.
Fluid spraying apparatus of this kind is disclosed by EP-A-0048091. The apparatus of EP-A-0048091 comprises a generally cylindrical body and two diametrically opposing nozzles that are arranged for rotation about the longitudinal axis of the body. The body comprises a fixed part and a rotatable part. The fixed part comprises an annular inlet portion defining an inlet passageway that accommodates a turbine, a mounting disk for mounting the turbine and an open-sided intermediate connecting portion between the inlet portion and the mounting disk. Said rotatable part includes generally cylindrical gear box portion that accommodates a gear train, that is connected between the rotatable part and the turbine, and a nozzle body portion that surrounds the open-sided intermediate connecting portion of the fixed part. Said nozzles are mounted on the nozzle body portion, each nozzle having the form of a truncated cone, the longitudinal axis of each cone being oriented substantially orthogonally to the longitudinal axis of the body.
In use, the apparatus is placed within a crude oil storage tank, and the inlet portion is connected to a pipe carrying a pumped supply of fluid, typically recirculating crude oil from the tank. The passage of the fluid over the turbine causes rotation of the rotatable part with respect to the fixed part, and thus rotation of the nozzles about the longitudinal axis of the body around the open-sided intermediate connecting portion of the fixed part. The fluid thus issues from the apparatus via the nozzles, and the length and taper of each nozzle are carefully selected so that the jet of liquid emerging has a comparatively small angle of spread.
A disadvantage of the fluid spraying apparatus of EP-A-0048091 is that owing to the back pressure generated within the nozzles, a high pressure pump is required.
A further disadvantage is that as the nozzles project to a substantial extent beyond the body of the apparatus, a large opening is required in a wall of the tank in order to insert the apparatus into the tank.
There is a requirement for a more compact fluid spraying apparatus which can be inserted through smaller openings in a crude oil storage tank as compared with those that are required for entry of the apparatus disclosed by EP-A-0048091. There is also a requirement for a fluid spraying apparatus which can be used with a low pressure pump of the kind that are readily available on site at oil refineries.
According to the present invention therefore there is provided a fluid spraying apparatus of the kind described comprising one or more of nozzles, characterised in that none of the nozzles extends radially of the longitudinal axis further than the body.
The fluid spraying apparatus of the present invention is thus extremely compact, and can be inserted through any aperture having a diameter greater than the maximum diameter of the body of the apparatus across the longitudinal axis thereof. Said apparatus may have a maximum diameter of no more than 46 cm (18 inches), and in one embodiment, the maximum diameter of the machine is 31 cm (12 inches).
Preferably the or each nozzle is generally frustoconical, and the longitudinal axis of each nozzle extends substantially orthogonally to the longitudinal axis of the body. The outer extremity of each nozzle preferably coincides with the outer extent of the rest of the machine. In some embodiments, the taper of each nozzle is in the range 10 to 40xc2x0, so as to minimise the back to pressure arising as a result of the constriction presented by the or each nozzle. Preferably, the taper of each nozzle is in the range 15 to 35xc2x0. The diameter of the opening in each nozzle will vary according to the specific application of the machine, but will generally be in the range 4-9 cm (1.5-3.5 inches). In some embodiments nozzle diameters of 5 cm (2 inches), 6.5 cm (2.5 inches) or 7.5 cm (3 inches) may be provided.
The body may comprise a first fixed part that is adapted to be connected to a pipe carrying a pumped supply of fluid and second rotatable part that is arranged for rotation about said longitudinal axis. Said nozzle(s) may be mounted on the rotatable part.
Said fixed part may comprise an annular inlet portion defining a passageway that accommodates a turbine arranged to be driven by fluid entering therein; a disk portion for mounting said turbine; and an open-sided connecting portion between the mounting disk portion and the inlet portion.
Said rotatable part may comprise a generally cylindrical gear box portion that accommodates a gear train connected between the turbine and the rotatable part; and a generally cylindrical nozzle body portion that surrounds the fixed part. Said nozzle(s) may be mounted on the nozzle body portion.
Preferably, two nozzles are provided, and these are ideally positioned diametrically opposite one another on the nozzle body portion around the open-sided intermediate portion of the fixed part. Thus, fluid entering the fixed part via the inlet portion debouches the apparatus through the open-sided connection portion of the fixed part and through the nozzle(s).
In some embodiments, the open-sided intermediate connecting portion of the fixed part may comprise a semi-cylindrical baffle wall that is connected between the annular inlet portion and the disk portion. It will be appreciated by those skilled in the art that as the nozzles rotate about the fixed part, the semi-cylindrical baffle wall thus serves to obturate each nozzle in succession. This arrangement is suitable where the fluid spraying apparatus is to be positioned within a tank adjacent a wall of the tank, so that fluid is prevented from being sprayed directly at the said wall in order to avoid damaging the wall.
Alternatively, the intermediate connecting portion may comprise a plurality of circumferentially spaced fingers which are dimensioned so as not to prevent any significant obstacle to the passage of fluid through the nozzle. In this case, the apparatus is suitable for use at or towards the centre of a crude oil storage tank, for example, away from the way, so that the jets of sprayed fluid emerging from the apparatus can be directed in all directions radially outwards of the longitudinal axis of the body.
The apparatus of the present invention is suitable for connection to a supply of fluid at a pressure of 4-8 bar, and is adapted to provide a flow rate of 400-700m3/hr.
Following is a description by way of example only with reference to the accompanying drawings of embodiments of the present invention.